It is well known that various galvanometric devices can be used to detect and record the minute differences in potential between different parts of the body caused by muscle action. Perhaps the most well known such device is the electrocardiograph which measures these differences for the heart muscle. In any event, and regardless of the particular muscle action being measured, it is frequently necessary or desirable to monitor the muscle's activity over an extended period of time. This is particularly so where the heart muscle is involved.
For the particular case involving the heart muscle, it is known that some heart anomalies can be identified early and properly diagnosed by studying a history of the patient's electrocardiogram (ECG). Further, it is known that some heart anomalies can even be effectively predicted by observing trends which are disclosed in the ECG history. In order to observe these trends, however, it is necessary that the heart be continuously monitored. This, of course, requires that the patient remain "hooked up" to an electrocardiograph for an extended period of time. Additionally, in order to be useful and effective, it is necessary that the ECG history be periodically reviewed by a physician. Consequently, the problem is essentially twofold. First, there is the need to detect and record the ECG history. Second, there is the need to safely, effectively and reliably transmit this ECG history to the proper medical authorities.
Fortunately, much of the world is serviced by a vast and extensive telecommunications network which is commercially available for the transmission of data and information between remote locations. Indeed, this existing network is accessible by various types of devices, to include telephones, facsimile machines, and central processing units. The present invention recognizes that the flexibility, reliability and conveniences of this network can, and should, be effectively used for the transmission of physiological data, such as an ECG history, from a patient to proper medical personnel. Where, however, it is necessary that the device remain connected to the patient while collecting this data (e.g. an electrocardiograph compiling an ECG history) it is essential that the patient be electrically isolated from the telecommunications network.
Accordingly, it is an object of the present invention to provide a device for relaying physiological data along a communications path from a patient to an electronic data processing system which electrically isolates the patient from the telecommunications network used by the electronic data processing system. Another object of the present invention is to provide a device for establishing a communications link between a patient and a data processing system which permits the relatively rapid unloading and transmission of data from the patient into the system. Yet another object of the present invention is to provide a device for transmitting collected physiological data which is safe to use with a commercial telecommunications network. Still another object of the present invention is to provide a device for collecting and transmitting physiological data from a patient which has minimal power requirements. Another object of the present invention is to provide a device for relaying physiological data along a communications path from a patient to an electronic data processing system which is easy to use, relatively simple to manufacture and comparatively cost effective.